Elastoplastic model for buckling-restrained braces: response and response sensitivity analysis

Buckling-restrained braces (BRBs) permit exploiting the hysteretic properties of their core material both in tension and compression. However, the global behaviour of BRBs does not fully replicate the local behaviour of their core material and requires the use of specific constitutive models. In this paper a recently developed elastoplastic constitutive model for BRBs is reviewed and its implementation in OpenSees discussed. Such model allows a straightforward physical interpretation and identification of the constitutive parameters as well as direct computation of response quantities related to failure and dissipated energy, with good predictions of the experimental behaviour. The algorithms implemented in OpenSees include response and consistent response sensitivity to the constitutive parameters of the BRB model. Selected results for response and response sensitivity analysis are illustrated and discussed using as testbed structure a realistic steel frame with BRBs